In article <3ohk87$5k2 at news0.cybernetics.net>,
chris at canada.medchem.purdue.edu (chris) wrote:
[snip]
->I was also trying to do nonlinearfitting to the following group of data:
->{0.5, 0.001}, {0.15, 0.005}, {0.1, 0.01}, {0.01, 0.1}, {0.001, 0.5}
->The function
-> 1-1/(1+0.00065/x)
->produces a curve (use LogPlot[1-1/(1+0.00065/x), {x, 0.001,1 }) that
seems
->to fit the data. However, when I used NonLinearFit with this function, I
->got the message that the function does not match a real number when
->x=0.001.
->Could someone help me on these two problems? Thanks a lot!
I would guess you had a syntax error. NonlinearFit worked ok when I used
models with either one or two coefficients to be fitted (you didn't specify
which coefficients were symbolic in your model):
data = {{0.5,0.001}, {0.15, 0.005}, {0.1, 0.1},
{0.01, 0.1}, {0.001, 0.5}};
NonlinearFit[ data, 1-1/(a+b/x), x, {a, b} ] (* fit two coeffs *)
{a -> 1.02788, b -> 0.000938836}
NonlinearFit[ data, 1-1/(1+b/x), x, {b} ] (* fit one coeff *)
{b -> 0.000981788}
Paul
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